Wayne Barnes, who maintains the collection of cars for the San Francisco Academy of Art, told KPIX-TV that he remembered how useful the bridge was before it was damaged.

"And so this is a big deal, especially for somebody from this area,” he said.

The project was marred by delays and cost overruns.

"Thank you for your patience, Bay Area!" state officials said in a Tweet on Monday afternoon.

The first cars, led by California Highway Patrol cruisers with flashing lights, started rolling across the bridge toward San Francisco about 10:15 p.m. Monday. As they did, motorists honked their horns by the toll plaza on the Oakland side of the bridge, according to television news reports.

Historic moment, the opening of the new span of the Bay Bridge! @ San Francisco-Oakland Bay Bridge http://t.co/1vuONJ1I8J